Gun



July 4, 1944.

H. SCHIROKAUER GUN Filed Sept. 24, 1941 5 Sheets-Sheet l July 4, 1944.

H. SCHIROKAUER sun - Filed Sept. 24', 1941 5 Sheets-Sheet 2 INVENTOR. Henry fic/u'ra/(m/e r,

y 1944- H. SCHI'ROKAUER GUN Filed Sept. 24, 1941 5 Sheets-Sheet 3 amen M300 l&btoww 8 g l'LWIIIiV/IA I July 4, 1944. H. SCHIROKAUER GUN Filed Sept. 24. 1941 5 Sheets-Sheet 4 5 Sheets-Sheet 5 GUN y 4, 1944- H. SCHIROKAUER Filed Sept. 24, 1941 W RH w A 7 ZEQE: litifii Patented July 4, 1944 UNITED STATES GUN Henry Schirokauer, New York, N. Y., assignor to Schirgun Corporation,"a corporation of Delaware Application september 24, 1941, Serial No. 412,168 r 4 Claims.

The invention relates to guns, but phases of the invention are not confined to any particular type of gun. All the elements involved in the invention, however, may be combined in a machine gun of the automatic, semi-automatic or self-loading and operating types. Such a gun may comprise in general the gun barrel with which is associated the receiver or cartridge chamber and cartridge feeding and firing mechanism. The firing mechanism may be controlled by a trigger device. With the barrel may be associated a gas cylinder tube. Connecting the barrel and the gas cylinder tube may be a gas muzzle or mechanism having a channel for leading gases from the fired cartridge to the gas cylinder tub where they may operate some or all of the gun mechanism. The present invention contemplates improvements in substantially all of the gun elements.

In the gun barrel and leading to the gas transmitting mechanism may be holes formed in an improved manner as so as to receive a sufficient quantity of the gas in a way to accomplish the desired purpose. The gas muzzle which transmits the gas to the gas cylinder may be so formed as to receive the gas and consume some of its energy. This preferably is done in a manner to effect a more or less smooth operation without sudden kicks or jerks. In the gas muzzle suificient energy of the gas may be consumed to act as a complete counter-recoil device for the sun so that there is substantially no kick or recoil at the stock or firing end of the gun. Sufiicient active gas for operation is fed to the gas cylinder tube but before it arrives there means may be provided for releasing some of the gas when excess of energy might otherwise be introduced. The relieving gas outlets may be controlled by an adjacent device to vary and regulate the gas conditions.

The gas cylinder tube is provided with a reciprocating piston on the piston rod of which may be mounted a mechanism for feeding or advancing the cartridges and also a conveyor for ejecting the cartridges from the cartridge belt when used and feeding them to the cartridge chamber. The piston rod may also carry the breech block in which may be incorporated the firing pin and the extractor for the empty shell. The piston rod may be provided with a clutch mechanism for rotating the cartridge feeding device and for operating the clutch a suitable cam mechanism may be provided. Also mounted on the piston rod may be a spring which acts as the spring for holding the clutch in engagement and also acts as th spring for returning the rod against the spent gas pressure and so feeding the cartridge to the gun and firing the gun. For convenience of assembling, disassem- 5 bling, handling and operation the mechanism carried by the piston rod may be assembled and fastened together as a unit.

The operation of the firing means may be controlled by a sear. A unitary casing may carry the scar and the trigger operating mechanism for controlling the firing of the gun. Preferably the trigger mechanism as a unit may be removed from the gun. The trigger casing may carry a spring controlled locking device for holding the sear in position to prevent firing the gun. In the trigger frame may be a trigger structure which preferably may move the sear to release the firing apparatus and then release the sear to return to its non-firing position. The'trigger may also include means for moving and holding the sear in firing position so that the gun mechanism may befree to fire automatically repeatedly rapidly. The trigger may be provided with a stop controlling mechanism to limit the movement to a single firing operation. Preferably this stop mechanism may be arranged so that additional force placed on the trigger may release the stop and allow the trigger to proceed to the position to hold the sear for automatic rapid firing of the chem.

The breech block mechanism which preferably will be earried by the piston rod may reciprocate in the receiver. It may include a member pivoted to a support carried by the piston 33 rod. Preferably this will be mounted by a loose motion mechanism such as a pin riding in a slot. The contact surfaces of the support and the breech block may have a cam action so that in one position of the loose motion mechanism the iot breech block may be free to turn on its pivot while in another position. of the loose movement mechanism it may be locked against turning. The breech block may carry an extractor mechanism which in one pivoted position may be away from the cartridge and in the other pivoted position may engage the shell to extract it from the barrel. carry the firing pin in such a way that in one pivoted position it may be held away from the cartridge while in another pivoted position it may be forced against the cartridge cap to fire the gun. The conveyor may deliver the cartridge to such a position in the receiver that it will force the empty shell from the gun. After the incoming cartridge reaches this position The breech block may also The conveyor preferably may be mounted on the piston rod so as to reciprocate therewith but be free to turn thereabout. The movement of. the

conveyor may be 'efiected and controlledin any" suitable manner such as by a pin' thereon engaging a suitable cam or cam slot in the gun casing. The cartridge may be engaged by the conveyor and moved to a position near the rear end of the .receiver and then the turning move merit of the conveyor'may force the cartridge into proper position to be fedinto the barrel' by appropriate mechanism suchas the breech blockin coordination with the conveyor. The conveyor may be'so formed as to engage the groove at the base of the cartridge which may 'be so proportioned and so arranged with respectto the other parts of the gun that the cartridge cannotbe'displaced from the conveyor untilit isfinally releasedin its final feeding position. This may'b'e accomplished by. causin'g the space between the conveyor and the adjacent portions of the frame to be. less than the diameter of the cartridge so that it may not slipithrough. Thecartridge seat in the conveyor maybe somewhat elevated sothat when the conveyor'reaches its final position the cartridge will drop away and allow clearance for the return movement of tl'i'e'conveyor.

"The gun may be provided with bearing means rotatable pin wliich may bind the barrel against thefrarneand hold the parts rigidly together.

In' order toinitiate operation of the gun, to feed in an initial cartridge or to take care of emergencies caused by failure to fire, misfiring, etc.,-

hand operating means may-be provided on the outside of r the gun for operating the movable parts. Likewise the mechanism for feeding in the cartridges even when in a cartridgeibelt may be manipulatedby'mechanism accessible to hand operation from the outsideof the gun.

' The various 'p'arts of the gun may be held together by means which may be manipulated-by hand and without the use of complicated tools.

This may be especially important in connection with mounting and dismounting the trigger mech-'- anisrn, the frame and the piston rod carrying the conveyor; the breech block, etc.

The entire mechanism has been so designed,

constructed and associated as to provide a gun.

of relative simplicity, of light weight and of small size especially with respectto over-all length of the gun. The parts may be conveniently and accurately made in quantity so that they are interchangeable'an'd replaceable and maybe convenientlyg economically and rapidly assembled into the various sections and thecompleted gun.

The invention 'may' be incorporated in various specific structures and is not confinedto specific details} Without limiting the invention specific apparatus embodying the invention is disclosed in the accompanying drawings and will be spe-' cifically described so as to further and fully explain the invention.

In the accompanying drawings Figure 1 is a side elevation of a gun taken from the left. Fig. 2 is a'fragmentary side elevation of the gun taken. from the right. Fig. 3 is a transverse vertical section on the line 33 of Fig. 1. Fig. 4 is a longitudinal vertical sectionof a portion of the gun. showing the, trigger and other operating parts. Fig. 5 is alongitudinal vertical section of a the muzzle end of the gun. Fig. 6 is a horizontal section throughthe muzzle end of the gun upjT-"wardly showing associated parts.

Fig. '7 is a fragmentary'section on a larger scale showing the mechanism for'loc'king the barrel to the frame. Fig. '8 is a fragmentary vertical section on the line 8-8 of Fig. 4.' Fig. 9 is a side elevation of the piston rod and parts carried thereby. Fig. 10

is a fragmentary longitudinal vertical section tion delivering ithe cartridge to the receiver.

.40: for the trunnions of a stand or the like. Apertures opposing 'each other in the' barrel and frame may be so formed that they may receive a showing the breech lever and associated parts in retracted position. Fig. 11 is a side' elevation of thebreechlever in retractedposition. Fig. 12 is a fragmentary longitudinal vertical section showing in firingposition an optional form of firing pinand-associated' parts. Fig. 13 .is a similar view of the partsof Fig. 12 in partially retracted position. Fig." 14 is a transverse 've'rticalsection on the.line1M!4 of. Fig; 4 but with the piston in retracted position? Fig. 15 is a fragmentary transverse vertical section .on the line [5-45 of Fig. 4 looking to the right. Fig. 16 is a fragmentary transverse. vertical section on line l5-I5 of Fig. Hooking t'o'the left showing the conveyor infiposition when it first engages a cartridge. Fig.- 17 is a viewjsi'milar to Fig. 16 on line Il -l1 of Fig. 4 showing the-conveyor inits final posi- 18 is a transverse vertical section on the line I 8-18 of Fig. 4. Fig. 19-is a' longitudinal vertical sectional view through the frame member. Fig. 20 is a fragmentary vertical longitudinal section through-a gun with another form of reciprocating piston. Fig. 21 is a section similar to Fig. 20'showingthe parts in another position. Fig. 22 is a fragmentary'top plan view of the casingwithythe cover removed showingthe slot controlling the conveyor.

. .The gun is provided'witha barrel 3| and a gas tube. 32 substantially parallel thereto. At its muzzle :end the barrel bore may be slightly en- ,theenlargedgportiom33 of the muzzle of the gun are holes 36.3These holes are preferably somewhatgoval and have their outer walls 31 at an angle of less than 23 to the walls of the gun 'barrel. Theopennigsj'36 communicate with a channel 38 in the gasimuzzle 34. The channel 38. iscarch' shaped or semi-circular, having 'a curved outer wall. The channel 38 leads to the interior of the gas :tube 32 and impinges on a pis ton139 movable'therein. Near the entrance to the gas-tube 32 are holes. 40 open to atmosphere. A shutter member 4| 'pivoted'at 42 to the gas muzzle 34 may be moved or adjusted by a handle 43 to regulate and control the amount of the holes 40.1eft open. F v

The gas muzzle device may be made of a casting 3-4 provided with a cover plate I30 at one side which maybe fastened in place'in any-suitable manner. By this construction it is possible to manufacture the gas muzzle device by simple machine operations. *Thus the openings for the ga's tube 32 and the end of 'thebarrel"3l' may be bored from the end of the casting34. The casting may then be turned on its side and from the side which is toreceive the cover I30 the remaining operations may be performed. The hole'36 may be drilled as deeply as may be needed, and may be properly formed. The hole 40 may be drilled entirely through the casting 34. With an end mill machine the channel 38 maybe formed. The hole to receive the pivot bolt 42 may be drilled entirely through the casting 34. The cover I33 may then be prepared by drilling through it the continuation of the hole 4!] and a hole through maythen be fastened rigidly in place and the valves 4l' mounted by means of the pivot pin 42.

As the gun 'is fired and the bullet passes through the'gun barrel the propelling gases un der pressure follow the bullet. As the bullet approaches the muzzle of the gun it passes the holes 35 and a portion of the following gases become free to pass through the holes 36. Because of the small 23 angle made by the wall 31 there is not an abrupt change in the direction of the gases and a kick or shock may thus be avoided. The gases continue through the curved channel 38 and tend to press upon the forward curved wall thereof in such a way as to counteract the irregular or kicking action of the gun. The effect of this may be tokeep'the gun more or less steadily in one position'and make it easy to handle and manipulate and at the same time not materially interfere with the aim or direction of shooting. As-the gases pass through the channel 38 which directs them backwards 180 they enter the gas tube 32 and impinge upon and move the piston 39 for a purpose to be explained. The amount of energy remaining in the gases may be very large and may be more than is necessary to'operate the piston 39. The pressure may be relieved by allowing a suitable portion of the gas to exit through the openings 40. The valves 4| maybe adjusted and set at a proper position to give the desired relief and procure whatever pressure is desired on the piston 39.

The piston 39 carries a piston rod 44 which is shown asa hollow tube.

Mounted to rotate freely on the piston rod 44 is a feeding spool 45. The spool 45 has two toothed wheels on it, 46 and 41,-which are adapted to engage cartridges fed to the gun. The rod 44 when pressure is brought on the piston 39 may move longitudinally through the spool 45 which is held from'longitudinal movement by a portion 48 of the housing for the gun passing between the wheels 45 and 41. A clutch member 49 held on the shaft 44 by a transverse pin 55 is held in engagement with the spool 45 by a spring 51 carried by the rod 44 andbearing on the collar of the clutch member 49. The pin 583 rides in a cam slot 52 in the rod 44 so that on each reciprocation of the rod 44 the clutch 49 rotates the spool 45 one step so as to advance a cartridge to be fed to the gun. Behind the spool 45 there is mounted on the rod 44 a conveyor 53 which as the rod 44 moves longitudinally removes a cartridge from the chamber associated with the feeding mechanism and delivers it to the receiver 54 of the gun. As illustrated especially in Figs. 16, 17 and 18 the cartridges are fed into .a transverse chute 55 by hand or by a belt or by suitable means not illustrated. Rotation of the feed spool 45 advances the cartridges one at a time until the lowermost cartridge reaches the position indicated at the right in the bottom of Fig. 18 where it is resiliently held by a spring 55. The feed spool 45 isnormally held against reverse movement by a lever 51. controlled by a spring 58. The holding lever51may be released by hand pressure from the outside of the gun s'o as to remove or feeder manipulate cartridges if the need arises. The spring 5| extends between the clutch member 49 and the piston 39 and normally holds the piston 39 in the muzzle end of'the gas cylinder tube 32. In this positiontheconveyor 53 is in the position indicated in Fig. 16. As is shown in Fig. 9 the arm of the conveyor 53 is provided at its end with a cavity provided with a rib 59 adapted to engage the groove in the base of a cartridge. The front edge of the cavityis bevelled at 60 so that it may slide between the lower two cartridges as illustrated in Fig. 16. 'In this position it will grasp a cartridge,.sufficient,movementior its entrance being provided by the resiliency of the spring 56. The conveyor 53 is mounted on the rod 44 by means of a pin 6| which rides in slots 62 in the rod 44 so that the conveyor cannot move longitudinally on the rod 44 but is free for a partial rotary movement thereon. The protruding end of the pin 6| rides in a slot 63 in the casing of the gun. The form of the slot 63 is illustrated in Fig. 22. A cover 64 for the slot 63 is shown. The slot 63 controls the rotary movement of the conveyor 53and is so formed that as the piston 39 moves in the gas tube 32 the conveyor 53 moves the cartridge which it has grasped backward into line with thereceiver 54 and then inward toward the center of the barrel into the position shown in Fig. 17.

It will be noted that the'inner point I20 of the rib 59 in the conveyor 53 as shown in Fig. 16 is positioned less than the diameter of a cartridge X from the adjacent portion l2! of the gun housing. It is therefore impossible for the cartridge to fall down. As the conveyor 53 moves from the position illustrated in Fig. 16 to a position illustrated in Fig. 1'7 the point iZEl always keeps nearer to adjacent partsof the structure than the diameter of the cartridge. Thus the corner i22, as the cartridge sweeps over it, keeps the cartridge inits seat in the conveyor but as the conveyor reaches the final position indicated in Fig. 17 the cartridge drops downward vertically into a position which is below the'corner l20of the conveyor 53 and with the cartridge in this position the conveyor 53 may turn counter-clockwise from the positionindicated in Fig. 1'? without engaging or disturbing the cartridge X and so return to its normal position to grasp and convey another cartridge. By this arrangement the cartridge as it approaches the position indicated in Fig. l7 strikes and forces out of the gun at 8| the empty shell which has been brought back by the extractor but the new shell itself is prevented from going out of the gun by the restricted distance between the corner I20 and the corner l22a.

Behind theconveyor 53 there is rigidly mounted on the rod 44 an inverted U-shaped supporting block 65, the dependingarms of which are provided with bearing slots 56 in which is mounted a pin 61 carrying a lever 68 whichacts as a breech block for the gun. The pivoted breech lever 68 travels forward and'backward in the receiver 54. In its backward position the'breech lever 68 as illustrated in Fig. 10, is in position to receive the cartridge from the conveyor 53. The lower end '59 of the breech lever is shaped to receive the groove-at the base of a cartridge X. The breech lever 581is free to turn on the pin 51 as a pivot. The breech lever at its upper end is provided with acam extension-lll-so formed that itengages the.

. barrel 3 I.

under part of the supporting block 65and forms a limiting stop for the rotary "movement of: (the breech lever 68. The breech lever 68 isso'mewhat the shape of an inverted T and its extending arms are provided with fiat surfacesll which jas indi-. cated in Figs. 10, 11 and 15 are in contact-with the curved edge 12 of the lower ends of the supporting block 65. In this position forwardmovement of the piston 39 underthe'influence of-the spring causes thecurved surfacelZ-to bear against the surface H and force the breech lever to advance and take its position behind-the barrel of the gun as indicated in Fig. 4. It will be observed that during this movement the pin .61 of the breech lever is in the front end of the slots 66. As the breech lever moves it rideson the surface 13 of the gun frame 1 1. As the breech lever approaches the position indicated in .Fig. "4 its forwardend may fall down through the hole 16 in the gun frame 11 and come to final position. to close the breech ,of the gun. To aidthis action the lower edge of the breech end of the gun barrel may be bevelled asat 14 and the'frontend of'the breech lever 68 may be correspondin'gly'bevelled at 15 so that as the breech-leverSB approaches the position indicated in Fig. 4 the engagement bee tween the surfaces M and 15: causes the breech lever to turn downward on its pivot 61:,and' 'drop into a hole 16 in-the gun frame 11. Carriedby the breech lever 68 1s a firing pin 18which remains out of contact'with the cartridge until the breechlever turns on its pivot 61. As the breech lever support approaches its final position, indicated in Fig. 4,.thebre'ech lever 68 tulns and further movement of the support 65causes the pin 61 to ride in the slot 66 so that as indicated'in Figs. 4 and 9 the'pin reaches the rear end of. the 5 slots 66. This tends to cause a hammer blow of the firing pin'18 againstthe cartridge primer'to fire the gun. The actual firing preferablytakes place shortly before the device'takes its final position. As the breech lever '68 turns'on' the 'pin 61 the surface H slides along-the curved surface 12 of-the breech lever support 65 and comes into contact with the flattened lower surface?!) of .the support 65; (See Figs. 4, 9an'd 11;) As the' 'slots 66 progress along the pint! thefiat'surfaces' H and!!! come into close contact and thus lock the breech lever against turning until the pin tilagain reaches the front end of the slot 66.1:Thusthe breech lever is locked against turningdnufirin position.- The backward movement. 'of' the'sup port 65 pulls. the slots 66 along the p'in"6'l' untilit reaches the frontend of the slots when it is free to turn and this turning "is caused by'contact' of the corner 80 of the hole 16 the frame 'l'l'with the back surface of the: breech lever 68. This turning causes the shaped surface 69at= the end of the breech lever, 68 as it rises'to engage the at the base of the fired shell and further'movement of the supporting block' extracts the shellfr'om the barrel and brings it back so that as thefhew cartridge is' brought'into position indicatedir'i Fig. 1'? it forces the spent'shellfsidewise and-our: ward through the opening B' I inthe'g'un casing. l" ""The gun'framemember 11 at its forward end abuts against a projecting ring or IugBZon'tHe' The barrel 3| isprovidedwith a' sul: stantially semicircular opening: 83.- "A similar substantially semicircular opening is provided in the facing surface of the'frame 111. The radii of these two openings are the same buttheir centers are slightly removed from eachother. Thus the center B ofth'e' opening M "may-be slightly to the right anddownward-atan angle ber- I0! may causeof about 45"from the center A of the opening 83 (see Fig. 7 "A pin '85 provided with'a turn:- ing handle 86=may beinserted through the openin'gs'83. and 84." The pin-85 is 'somewhat ellip 'tical in cross-section, having its upper forward portion formed onthe radius B and its lower rear portion formed on the radiusA; so that 'as the handle 86 is turned downwardly there is ate'ndency for the pin 85 to engage 83 with its upper righthand side and to'engage 84 with its lower left hand side soas towedge itself between the barrel 3| and the frame 11 and jam the frame 11 against the ring 82. The otherend of'the frame- 11 lies above the trigger frame 81 which is held in 'placeby the spring 88. g In a'depen'ding portion of the frame 11 'is 'provided'an opening '89for truri'nions for the usual gunsupport.-"

The scar and the trigger mechanism is enclosed as a unit in the trigger frame 81. To the trigger frame 81 may be fastened as by welding a trigger guard 90 extending upwardly and rearwardlyover-the trigger frame. Depending from theframe 11 is a notched lug 9l into ,the'notch of which enters aportion of the upper plate of the trigger guard 90'. At its rear end thereis a hook 92 ion the trigger guard which engages the gun'casing where it and the trigger frame: 81, of which it is a part, is held in position by the sprin 88 mountedfon thegun casing. The frame'l'lis provided with an apertur '93 through which extends a' sear 94 in position to engage and restrain from forward movement the breech lever 68 which carries thefiringpin and may be said to act as a'hammer for firing the gun. The sear 94 is pivoted on a pin 95 car'ried'in the trigger frame'iil. A rotating :pin 96, mounted to rotate in the trigger frame 87,has two fiat surfaces againsteither 'of which may rest a springtl,

mounted in the" trigger frame 81, to hold it in either of twdpositiOns. As illustrated in Fig.1 one of thefla't surfaces of the pin 96 makes room for movement of 'the' sear 94' about its pivot 95. When the pin 96'isiturned inclockwisedirection the unfiattened portion of the pin rests against the lower part of the'sear 94 and locks it against movement. This locks the gun againstjop'eration. v A spring ss'm the triggerjfrarnebears on the lower arm of the sear 94 and holds its upper end projected. A spring 99 in the .t'riggerframerests against a pin l 09 on a trigger member! 0| which is pivoted at I02 in the trigger frame. Pivot'ed at I03 in the pivoted trigger member lllllisza' trigger pawl I04 which is'normally held inch.- gagement withthe lower arm of' the searl94 'by a" spring I 65." Upward movement of the trigger pawl l04 is limited by means of across bar I66 carried by th triggermember llll. Pressureof the'operators finger on the causes the trigger pawl l64to turn the sear 9491i its pivot 95 against the spring 98 andwithdraw it from the path of the breech lever 68.1 As this movement takes place the pawl lMjslides. down and away from the depending arm of 'thesearS A and releases it and it maybe returned. by the" be oftsome such material asrubber orthelike so that increased pressure on" the trigger;

th -ball to recede and allow t s rm m r 1 ml and engage'the the trigger member IIlI to move further. This further movement of the trigger IUI on its pivot I02 .will cause thecross bar I06 to engagethe lower arm of the sear 94 and hold the nose of the seardepressed or retracted for as long as the trigger is held. Thus a movement of the trig er Illl limitedby the balls IIJI will cause the gun to fire a single cartridge while fulLmovement of the trigger member ,I III beyond the stops III! will place the gunin position for automatic repeated firing.

The gun housing I23 .carries projecting pins I09 (see Figs. 1 and 3) which are curved to form a guideway for a sliding frame III) which is provided with a projecting handle I I I and a depending lug H2. The dependinglug II2.engages an outwardly projecting lug II3.on thebreech lever support 65. .By means of the handle II I. the cam I I2 may be slidbackward on, its bearing pins I09 and it may thus force the supporting member 55 and the piston rod 44 to which it is attachedin the same direction as the gases of explosion forces it. Thus the operation ofthe gun may be initiated by hand since the mechanism described forms a recocking mechanism for the gun. By this means the gun may be manipulated when empty, it may be initially charged, and it, may be examined, etc., in case of misfire or other mishaps. Suitable releasable means may be usedto releasably lock the handle III or the slide H in normal position when not in use.

The gun housing I23 is held in position by forwardly projecting ears provided with holes I24 through which passes the pin or rod 85 which holds the frame II to the barrel 3I. A portion 48 of the housing passes over the spool 45 carrying the wheels 46 and 411. At its rear end the housing I23 is closed by a downwardly extending wall I25 in which is the opening to receive the hook 92 of the triggerframe 81. Th hook 92 thus holds together the housing I23 and the frame member 11.

It will be noted that the breech lever 68 is a single piece which acts not merely as means for closing the breech but also carries a firing pin and a unitary extractor for the shell of the fired cartridge. This is an advantageous arrange.- ment and may be highly desirable. Another arrangement, however, may be used, in which the firing pin may b a separate member and in which the extractor may be a separate member. As illustrated in Figs. 12 and 13 the breech lever support 65a may carry a breech lever 68a which may be provided with a pin B'Ia riding in slots 66a in the support 65a. The breech lever 68a is provided with an extractor tip H4 which may be a separate piece held in place in any suitable way such as by means of a rivet II5, so that in case of wear it may be replaced. A depending lug H6 carried by the supporting member 65a may be provided with a firing pin 18a adapted to pass through an aperture III in the breech lever 58a. In this construction the firing pin is separated from the breech lever and the firing is effected only when the supporting block 65a is advanced so that the pin 68a is in the ex treme rear portions of the slots 66a illustrated in Fig. 12.

It will be observed that substantially all of the work of the gun is accomplished during the power stroke. Thus the movement which accomplishes the unlocking and retraction of the breech lever and feeding of the cartridge and its conveying to the cartridge chamber is effected by gas pressure during the recoil stroke. The relatively easy procedure of inserting the cartridge into the barrel and firing the cartridge is all that need be accomplished by the expansion of the spring which has been compressed by the effect of the gas on the piston head in the gas cylinder.

The various partsof the gun are connected together in units in a simple way. The gun may be readily taken apart or separated into its units by a simple procedure and mainly without the use of tools. The shaft may be turned so as to loosen it in its bearings and it may then be removed laterally. In this condition the barrel of the gun may beremoyed for inspection, cleaning or replacementif necessary. The gas muzzle 34 maybe removedwith the barrel, being merely slipped off theend of the gas tube 32. The nut 35, however, may be removed and the gas muzzle as a unit freed from both the barrel and the gas tube. If it is desired to further dismantle the gun the trigger frame 8I may be moved rearwardly against the spring 88. Thiswill allow the trigger guard frame to be withdrawn from the slot in the block SI and the trigger frame may then be turned downward and finally released from the spring 88. The housing I23 is thus freed by the removal of the pin 85 from its forward end and by therernoval of the hook 92from its rear end. The housing I23 may now be removed. This exposes the rear end of the gun and makes it possible to withdraw from the gas cylinder the entire unit illustrated in Fig. 9 consisting of the piston and its red carrying the spool for advancing the cartridges and also the cartridge conveyor and the breech lever with its support.

In Figs. 20 and 21 is shown another form of gas muzzle and a piston especially adapted to cooperate therewith.

With the piston in the most forward position the breech block'lever 68 is in the position shown in Fig. 4 and in Fig. 20. The initial backward movement of the piston does not require a very greatamount of energy since the beginning of the movement in addition to moving the conveyor 53 merely pushes the supporting block backwards so that the slots 66 ride on and finally engage the pin 61. At the same time the forward or gripping shaped surface 69 of the pivoted breech lever 68 is lifted into contact with the rim at the base of the fired shell. Up to this point in its movement no considerable energy is needed. Further movement causes the pivoted breech block to act as an extractor to pull the shell from the barrel of the gun. Sometimes the shell will stick and it may be that considerable energy is needed for its loosening. After it has once been loosened its further movement may be easier and may not require so much energy. In order to take care of this particular requirement and in order to control more regularly the movement of the piston and other parts of the gun a special form of piston illustrated in Figs. 20 and 21 may be employed. Thus the vent hole in the muzzle attachment may be placed slightly further backward as indicated at 40a. The piston 390. may be provided with a tube-like forwardly extending member 3%. In the side of the extension 39b may be provided a hole 4% which, if desired, may be made somewhat elliptical. The hole 401) is so placed that when the piston is in its normal full forward position as indicated in Fig. 20 it is in register with the hole 40a so that when gas from the fired cartridge first enters the gas cylinder 32 it will impinge on the piston 39a but the pressure may be relieved somewhat by free passage of the gas "through the holes 40a and 40b. The'piston thus' is"causedto move re'arwardly and as it, moves it brings the openingsADa and'dllb out ofre'gisterf indicated in Fig. -'21, this'prevents'the' Kit of gas: Closure of the outlet "port preferably PW'i'll-"come just before the pivoted breech} block 6 8: reaches the position indicated in Fig. "21f*sbthat as the extractor 'moves' the fired *she1l fr6mthe barrel of the gun the full pressureoff the'gas is exerted on the piston head,

th giving theincreased power which maybe de able atthi'stime. In order" to relieve the pr sure inthe 'latter part of the stroke,"how-" everi the extension 39bof-the' piston head 39a as it proceeds 'iswithdravvn'fromthe hole40a and thus thegas pressure is again relieved.

If the full press'ureof the gas were employed'in the firstpart-ofthe movement of the piston it might be that the impact or hammer blow ofthe extractor againstthe endiof the fired shell as the extractor'reaches the position" in Fig; 21 would be such-as to'injure or d'eformfthe-rim of the cartridge; For'this reason there may be an advantage in relieving the pressure in the first part ofthe movement and i'n'increasing the pressure during thefactual extracting movement. This and'other phases of the present invention may be especially important in" guns of larger caliber Where the gas pressure is largeand the impact or effecton the parts maybe strenuous;

which may be manually operated through the gun casing, the cam surface being constructed andarranged to actuate the clutch as the shaft moves from its" normal [position and to release the clutch as the shaft returns to'it's normal position; I r '2; In a gun,-a feeding mecl'ianism' for cartridges comprising means for advancing the cartridges, a clutch constructed and arranged to ac.- tuate the advancing means, a reciprocable shaft on which the clutch is mounted, a cam surfacein the shafteng'aging the clutch to operate it, and a compressible spring surrounding the shaft and holding the clutch in operative position andtend ing to move the shaft toi'ts'normal position.=: '3. In a gun, a 'gun casing, a feeding mechanism for cartridges fmounted'in' thegun casing com prising means for advancing the cartridges,.a clutch constructed and arranged to actuate the advancingmeans;areciprocable shaft on which the clutch is mounted, acam surface in the shaft engaging the clutch tooperate it, a'compressible spring surrounding the shaft and holding the a clutch in operative position and tending to move the shaft to itsnormal position, and a stop for the advancing means mounted on the gun casing which may be manually operated through the gun casing. i r

1. In -a gun, a feeding mechanism for car tridges' comprising means for advancingthe cartridges, a clutch eonstructedand arranged toac tuatethe advancing means, a reciprocable shaft on which the clutch is mounted; a compressible spring surrounding the shaft and holding the clutch in operative position and tending to move the shaft to its-normal position; and'a cams'urface in the shaft being constructed-and arranged to'actuate the clutch asthe shaft moves from'its normal position and to release the clutch as the shaft returns to its normal position. r

I-IENRY SCI-IIRQKAQUER."

7 CERTIFICATE OF CORRECTION. Patent No. 2,555,118. July 1;, 19m.

' HENRY SGHIROKAUER.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 5, first column, line 15, after the word "through" insert which the pin L;.2 may pass. The cover plate 150"; and that the said Letters Patent should be read wiih this correoti on therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 15th day of Apgust, A. D. 191m.

Leslie Frazer (Seal) Acting Commissioner of Patents.

CERTIFICATE OF CORRECTION. Patent No. 2,555,118. July 1;, 191m.

HENRY SCHIROKAU'ER.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 5, first column, line 15, after the word "through" insert which the pin 142 may pass. The cover plate l50--; and that the said Letters Patent should be read wiih this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 15th day of Apgust, A. D. 19bi Leslie Frazer (Seal) Acting Commissioner of Patents. 

